The Nuclear Regulatory Review and Nuclear Site Licensing

As readers will recall from an earlier blog post[1] in this series, in March this year the Government published its response to the Nuclear Regulatory Taskforce’s 2025 review (“the Review”). In its response the Government committed to implementing the Review’s 47 recommendations as quickly as possible.[2] This blog post considers the way in which the proposed changes to the nuclear sector will affect nuclear site licensing, and some of the steps that the Office for Nuclear Regulation (“ONR”) has already taken to implement the recommendations of the Review.

Nuclear Site Licensing and the role of the ONR

The nuclear site licensing process is one of the ONR’s main statutory functions. The key piece of legislation governing the nuclear site licensing regime is the Nuclear Installations Act 1965 (“NIA 1965”). Section 1 of the NIA 1965 prohibits the operation of nuclear reactors, and certain other defined installations, without first obtaining a nuclear site licence. The ONR’s discretion as to whether to grant a licence, and if so on what terms, is broad. Sections 3 and 4 of the NIA 1965 provide some statutory restrictions, including that licences may only be granted to a body corporate, are not transferable, and must be granted subject to such conditions as the ONR “considers necessary or desirable in the interests of safety”. The question of what licence conditions are necessary or desirable is itself a matter for the ONR’s discretion.

The way in which the ONR has approached its licensing function is explained in the guidance document Licensing Nuclear Installations.[3] The ONR’s focus is on safety and risk management, including through the application of the ONR’s Safety Assessment Principles (“SAPs”). At the time of writing the ONR is currently undertaking a public consultation on the SAPs revision.[4] The consultation will run for eight weeks, closing on 18 September with the final version of the SAPs expected to be published in December 2026.

In terms of the conditions attached to licences, the ONR has a set of 36 standard licence conditions that it attaches to all nuclear site licences. Several of the standard licence conditions make reference to the requirement for licensees to produce and implement ‘safety cases’, which are defined by licence condition 14 as “documentation to justify safety during the design, construction, manufacture, commissioning, operation and decommissioning phases of the installation”.[5]

Nuclear Site Licensing and the Review

The proposals set out in the Review, which have been accepted by the Government, will have a direct impact on the nuclear site licensing process and the role of the ONR. I have highlighted three areas in which there is likely to be change below.

The first is that the implementation of the recommendations will lead to structural change in how nuclear site licences are granted and by whom. The Review recommended the establishment of a collective decision-making body for nuclear regulatory decisions, the Commission for Nuclear Regulation (the “Commission”), to consolidate decision-making in the nuclear sector. The Commission is therefore likely to play some part in nuclear site licensing, albeit the extent to which it will supplant the ONR’s existing functions is currently unclear. In the interim, the Review also recommended the adoption of a ‘lead regulator’ model by relevant regulators. The ‘lead regulator’ would effectively perform the Commission’s function in the short term in the period before legislation to establish the Commission comes into force.

The second area of change is in the production of safety cases. The Review was expressly critical of the way in which safety cases are currently produced. Safety cases were described as increasingly long, technical, and complex, placing a burden on established and prospective licensees. The Review therefore recommended that safety cases be simplified so that they are practical and usable by licensees. It also encouraged greater early engagement between licensees and regulators to establish simplicity as a shared objective and ensure alignment on risk management. Once implemented, changes in the production of safety cases may help to reduce some of the burden on licensees that was identified by the Taskforce. On the other hand, it is inescapable that safety cases will need to remain sufficiently detailed and technical to satisfy the ONR that the licensee is managing and mitigating nuclear risks appropriately.

The third and related area of change is in the approach to risk management in the assessment of licence applications. The Review was heavily critical of the sector’s current approach to risk management as being overly cautious. The Government has, in response, committed to establishing a Proportionality Action Plan to ‘reset’ the approach to risk management within the nuclear sector. The direction of travel appears to be very much towards a more ‘proportionate’ approach to nuclear risk management, which will inevitably change the way in which licence applications are assessed by the regulator. Risks that might currently stop a licence application in its tracks may, in future, be seen as acceptable.

The response from the regulator

So far the ONR’s response to the criticisms levelled by the Review has been cooperative and collaborative. The ONR has begun working with other regulators to start implementing the ‘lead regulator’ model recommended by the Review. Similarly, regulators and Government have started work on producing the Proportionality Action Plan.[6] The ONR has begun updating its own guidance documents in line with the Review’s recommendations, including its licensing guidance and its Technical Assessment Guides (“TAGs”).[7]

It is probably fair to say that none of the changes implemented by the ONR so far will lead to a ‘radical reset’ in the process for nuclear site licensing. We are however only a matter of months out from the Government beginning to meaningfully action the Review. Many of the more significant changes to the ONR’s work – including the establishment of the Commission, a more comprehensive review of the ONR’s SAPs, and the Proportionality Action Plan – are yet to come.

As a previous blog[8] in this series highlighted, given the potentially catastrophic consequences of failing to mitigate nuclear risks, it is important to ensure that appropriate levels of caution are not lost entirely in the efforts to streamline nuclear site licensing and improve efficiency. As progress in implementing the Review’s recommendations continues, it will therefore be interesting to see whether tension arises between the Government and the regulator when it comes to the drive towards proportionality in risk management.

[1] See: https://www.39essex.com/our-thinking/insights/a-radical-reset-or-regulatory-recalibration-a-legal-perspective-on-uk-nuclear-reform/#_ftn2.

[2] See: https://assets.publishing.service.gov.uk/media/69b3ead0b84f01b2be53a1de/building-our-nuclear-nation-government-response-to-nuclear-regulatory-review.pdf.

[3] See: https://www.onr.org.uk/media/30nh5c0f/licensing-nuclear-installations-2026.pdf.

[4] See: https://www.onr.org.uk/news/all-news/2026/07/nuclear-industry-and-public-invited-to-shape-new-regulatory-principles-for-future-uk-nuclear.

[5] See the ONR’s Licence Condition Handbook: https://www.onr.org.uk/our-work/how-we-regulate/nuclear-site-licensing.

[6] See: https://www.onr.org.uk/news/all-news/2026/03/positive-progress-made-on-nuclear-taskforce-recommendations-to-reduce-regulatory-complexity.

[7] See: https://www.onr.org.uk/news/all-news/2026/06/nuclear-safety-cases-reset-to-remove-complexity-and-duplication

[8] See: https://www.39essex.com/our-thinking/insights/a-radical-reset-or-regulatory-recalibration-a-legal-perspective-on-uk-nuclear-reform/.